APPLICATION OF DESIGN PATTERNS FOR HARDWARE DESIGN

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APPLICATION OF DESIGN PATTERNS FOR HARDWARE DESIGN
Authors R. Damaevicius, G. Majauskas, V. tuikys

• Speaker Prof. Vytautas TUIKYS,
• Software Engineering Department,
• Kaunas University of Technology,
• Kaunas, Lithuania
• E-mail vystu_at_if.ktu.lt
• Phone [phone]

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Content

• Reuse Context Motivation
• Domain Analysis Framework and Findings
• Soft IP-Based System-Level Design Processes
  Design Patterns (DP) Their Relationship
• Implementation Using Metaprogramming (MPG)
• MPG and DP-Based Design Framework
• Experiments
• Evaluation and Problems
• Conclusions

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Reuse Context Aim of the Presentation

• Reuse equations
• (1) Promises
• Quality Productivity Time-To-Market
• (2) Reuse
• Domain content Technology ...
• (3) Technology
• Component-based reuse Generative reuse
• (4) Activities
• Design Domain Analysis (DDA) ...
• Our aim
• To bridge DDA with automatic tools

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Domain Analysis A General Framework
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Domain Analysis A Summary of Findings

• Trends
• Shift towards Integration-based Design
• Blurring boundaries between HW SW design
• Well-understood sub-domains
• Communication-based design using well-proven
  communication models (Handshake, FIFO, etc.)
• Fault-tolerant design using well-proven
  redundancy models (TRM, etc.)
• Solutions for common design problems
  (System-Level Design Processes and Design
  Patterns)
• Explicit separation of variant and invariant
  parts
• Multi-language approach

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HW Design Processes Based on Soft IP

• Register Transfer-Level Design Processes
• System-Level Design Processes

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Layers of System-Level Design Processes

• Specification layer domain analysis and
  specification of design problems
• inheritance, encapsulation, etc.
• Generalization layer analysis and specification
  of generic design solutions
• separation of concerns
• composition

• Implementation layer solutions of design
  problems using reuse technology
• wrapping, etc.

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Design Pattern Definitions

• The design pattern is ...
• descriptions of communicating objects and
  classes that are customized to solve a general
  design problem in a particular context
• E. Gamma et al., 1995
• both a description of a thing which is alive,
  and a description of the process which will
  generate that thing
• C. Alexander, 1979

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System-Level Design Processes and Design
Patterns Relationship

• Our definition
• A System-level HW design process is a common
  well-defined HW design activity aimed at
  designing a system from soft IPs at a high level
  of abstraction
• Our definition
• A HW Design Pattern is theUML-based
  specification of a System-Level HW Design
  Process based on a well-proven design model

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Design Patterns in Hardware Design

• Pattern-like solutions proposed by others
• models of computation/control Finite State
  Machine
• communication models protocol, bus,
  communication co-processor
• wrappers reliability, bus, protocol, memory
  wrappers
• Design patterns adapted from SW design
• Abstract Factory, State Yoshida
• Resource Manager Vanmeerbeeck et al.
• Composite, Object Adaptor, Abstract Factory and
  Decorator Åström et al.
• Singleton Charest and Aboulhamid
• New HW design patterns
• Bus-Protocol, DLX Processor Architecture Doucet
  and Gupta

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Application of the OO Concepts for VHDL

• Abstract class (interface) - VHDL entity
• A class that implements an abstract class - VHDL
  architecture
• The composition relationship - VHDL port map
  statement
• Class attributes - VHDL ports and signals
• Class methods VHDL processes or procedures

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Wrapper Design Pattern

• Allows adapting an interface and behavior of the
  IP component to the context of a given application

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Specification of Design Patterns Using
Metaprogramming

• Metaprogramming (MPG)
• provides a means for manipulating with other
  programs as data at a higher level of abstraction
• uses two different languages in the same generic
  specification
• Metaprogram a program generator for a narrow
  domain of application

• Domain language (DL) (e.g., VHDL) describes
  domain functionality
• Metalanguage (ML) (e.g., Java) describes
  generalization and domain program modifications
  at a higher level of abstraction

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Summary of Metaprogramming Principles

• CI Component Instance
• R Requirements for modification/generalization
• S Separation of concerns
• P Parameterization
• I Integration of concerns
• MP Metaprogram

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Framework of Our Approach Implementation

• (0) Design Domain Analysis (DDA) SL Design
  Process/ Design Pattern, Requirements and soft IP
• (1) Metaprogramming describe the domain program
  modifications depending upon the values of the
  generic parameters
• (2) Parsing use the soft IP interface as values
  of generic parameters for metaprograms
• (3) ML processing generate the soft IP wrapper

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Experiments Based on Well-proven Models

• Communication interface synthesis
• Handshake Wrapper see paper DAC 03
• FIFO Wrapper - next slide for details
  INFORMATICA, see Ref. in DAC03
• Fault-tolerant design submitted, not presented
  here
• Space Redundancy Wrapper
• Time Redundancy Wrapper
• Data Redundancy Wrapper

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FIFO Wrapper Generator Implementation

• FIFO protocol is used in the producer-consumer
  communication model to smoothen bursts in the
  requests for a service

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Evaluation of Design Specification

• Advantages of using HW Design Patterns
• raise the level of abstraction
• capture the design content immediately and
  intuitively using UML diagrams
• enable the automated design validation and code
  generation
• Shortcomings
• do not provide with a full HW design
  specification for its implementation

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Evaluation of MPG-based Implementation

• Metaprogramming (MPG)
• bridges the Design Domain Analysis with Domain
  Generators
• allows to adapt soft IPs to the context of
  application using well-proven domain models
• increases the reusability and productivity when
  customizing third-party soft IPs

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Problems yet to be solved

• How the System-Level (SL) Design Processes
  described as the UML-based HW Design Patterns
  (DPs) could be (semi-) automatically transformed
  into metaprograms?
• How the physical constraints (e.g., the timing
  ones) should be reflected in an OO model (DP)?
• How the entire DP could be directly synthesized
  to RTL?
• What is a more precise model for describing
  correspondence between soft IP-based SL Design
  Processes and DPs?
• What is the best way for implementing DPs
  MPG-based, OO-based or other?

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Conclusions

• The well-proven dimension of a SL Design Process
  (e.g. wrapping) is a Design Pattern
• The Design Pattern brings the design content
• Both soft IP and metaprogramming bring technology
• Our methodology puts together the design content
  and technology, thus enabling better reuse,
  higher quality and productivity
• Future work will focus on the discovery of other
  HW design patterns and the development of the HDL
  code generators for their implementation

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APPLICATION OF DESIGN PATTERNS FOR HARDWARE DESIGN

• Thank You
• for Your attention !
• http//soften.ktu.lt/stuik/dac03/